GM Europe have been quite open with data and I hope it continues under the new ownership. However, I expect it to be absorbed into the PSA data. For now at least we can glimpse into the production volumes and where they are generated from.
The nations involved in vehicle manufacturing are Germany, Spain, Poland, the UK, France, Bursa (Europe). Elsewhere in South Korea. The facilities in France are owned by Renault and in Turkey run by Tofas in a joint production arrangement with Fiat. The Korean manufacturing is by GM Korea.
Now a rundown of what each plant makes, ranked by size:
Zaragoza, Spain: Corsa, Meriva and Mokka.
Gliwice, Poland: Astra and Cascada.
Rüsselsheim, Germany: Zafira, Insignia.
Changwon, S. Korea: Karl/Viva, Mokka.
Eisenach, Germany: Adam, Corsa.
Ellesmere Port, UK: Astra.
Luton, UK: Vivaro (van).
Batilly, France: Movano (van).
Bursa, Turkey: Combo (van).
Sandouville, France: Vivaro (van).
Bupyeong, S. Korea: Antara.
It will be interesting to see how plant utilisation unfolds in the future. There are a few other locations where powertrains are made (Austria, Germany and Hungary). For now the status quo will be maintained.
Data source: GM Europe.